But now macs use "bundles" which are somewhat similar to iRex approach. Basically the allow a folder (=directory in Windows terms

) to be seen as a single file in the file-browser. This way you can bundle multiple files. E.g. every application is in fact a bundle, containing the executable, all resources, libraries, etc.
So I kind of like the manifest-folder kind of thing, as on the mac, you could just mark this manifest-folder as bundle, so the user sees it as a single file